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Hepatitis B Basic Information

  • All healthy newborns are recommended to receive the hepatitis B vaccine within the first 24 hours following birth.
  • Progress toward hepatitis B elimination has stalled. In 2017, 32 states reported slight increases in infections.
  • New hepatitis B infections are highest among people ages 30-49 because many people at risk in this group have not been vaccinated as recommended.

What Is Hepatitis B?

Hepatitis B is a liver infection caused by the hepatitis B virus (HBV). HBV causes inflammation of the liver. When the liver is inflamed or damaged, its function can be affected.

  • The best way to prevent HBV is by getting vaccinated. Safe and effective vaccines are available and covered as a preventive service by most health plans.
  • Hepatitis B is transmitted when blood, semen, or another body fluid from a person infected with the HBV virus enters the body of someone who is not infected. This can happen through sexual contact; sharing needles, syringes, or other drug-injection equipment; or from mother to baby at birth.
  • For some people, HBV is an acute, or short-term, illness; for others, it can become a long-term, chronic infection. Risk for chronic infection is related to age at infection: approximately 90% of infected infants become chronically infected, compared with 2%–6% of adults.
  • Chronic HBV can lead to serious health issues, like cirrhosis or liver cancer.
  • Hepatitis B is diagnosed with a simple blood test that can detect hepatitis B infection years before symptoms develop and the virus has caused liver damage.
  • There is no cure for hepatitis B, but there are several FDA-approved medications that treat HBV. People with chronic hepatitis B should be monitored regularly for signs of liver disease and evaluated for possible treatment.

How Many People Have Hepatitis B?

In the United States, an estimated 850,000 persons were chronically infected with the hepatitis B virus in 2012. New cases of HBV infection in the United States had been decreasing until 2012. Since that time, reported cases of HBV have been fluctuating around 3,000 cases per year. In 2016, 3,218 cases of HBV were reported; however, because of low case detection and reporting, the Centers for Disease Control and Prevention (CDC) estimates that there were 20,900 acute cases of HBV infection in 2016. That is a higher than 5% increase compared to 2012. This increase in new HBV infections is a very concerning trend that CDC has determined is linked to the ongoing opioid crisis in the United States.

Globally, HBV is the most common blood-borne infection with an estimated 257 million people infected according to the World Health Organization.

Who Is Most Affected?

In the U.S., rates of new HBV infections are highest among adults ages 30-39 years of age, reflecting low hepatitis B vaccination coverage among adults at risk. The most common risk factor among people with new HBV infections is injecting drugs, related to the opioid crisis.

The highest rates of chronic hepatitis B infection in the United States occur among foreign-born individuals, especially people born in Asia, the Pacific Islands, and Africa. Over half of cases in the United States are among people who were born outside of the United States. CDC developed this map of the geographic distribution of hepatitis B around the world. Other groups who have higher rates of chronic HBV infection include people who inject drugs and men who have sex with men.

HIV and HBV Coinfection

HBV infection is fairly common among people living with HIV. About 10% of people living with HIV in the United States are coinfected with HBV, reflecting the shared modes of transmission for these two infections. People living with HIV are at greater risk for complications and death from HBV. All people with HIV are recommended to be tested for HBV, and if susceptible, are further recommended to receive the HBV vaccination or, if chronically infected, evaluated for treatment to prevent liver disease and liver cancer. For more information about HIV and HBV coinfection, visit HIV.gov’s pages about hepatitis B and HIV coinfection.

How Is Hepatitis B Transmitted?

Hepatitis B is spread in several distinct ways: sexual contact; sharing needles, syringes, or other drug-injection equipment; or from mother to baby at birth.

In the U.S. in 2016, injection drug use was the most common risk factor reported among people with an acute HBV infection, followed by sexual contact with a person with HBV infection. Less commonly reported risk factors included accidental needle sticks, surgery, transfusions, and household contact with a person with HBV. In the United States, healthcare-related transmission of HBV is rare.

Mother-to-child transmission of HBV is especially concerningbecause it is preventable. An estimated 25,000 infants are born to mothers diagnosed with HBV each year in the United States, and approximately 1,000 mothers transmit HBV to their infants. Tragically 90% of HBV-infected newborns will develop chronic infection, remaining infected throughout their lives. Up to 25% of people infected at birth will die prematurely of HBV-related causes. For this reason, the standard of care for pregnant women includes an HBV test during each pregnancy so that the appropriate steps can be taken to prevent HBV-positive mothers from transmitting the disease to her infant.

Globally, mother-to-child transmission and inadequate infection control in health care settings represent significant modes of viral hepatitis transmission. That is why immigrants from many countries are recommended to be tested for HBV as well as hepatitis C virus (HCV).

Hepatitis B Prevention

Hepatitis B is a vaccine-preventable disease. The hepatitis B vaccine is safe and effective and is usually given as 3 shots over a 6-month period starting at birth. A newly approved hepatitis B vaccine for adults requires only two doses given over 30 days, which increases protection among adults more rapidly with fewer medical visits. There is also a combination vaccine approved for adults that protects people from both hepatitis A and hepatitis B. The combined vaccine is usually given as 3 shots over a 6-month period. These tools may support increased vaccination in settings such as jails, prisons, and substance use disorder prevention and treatment programs.

Immunization programs for infants and adolescents that started in 1991 have resulted in substantial declines in the incidence of HBV infection in young people. Find out if you should get the hepatitis B vaccine. The Hepatitis B vaccine is a covered preventive service for those for whom it is recommended under many health plans.

Hepatitis B can also be prevented by avoiding contact with contaminated blood and unprotected sexual exposure. Using condoms has also been shown to reduce the chance of sexually transmitted infections.

Mother-to-child HBV transmission can be prevented by identifying pregnant women who are chronically infected and providing the infant with hepatitis B vaccine and hepatitis B immunoglobulin at birth. Recently updated guidelines also recommend that pregnant women with chronic HBV be referred to a specialist and considered for HBV treatment to further reduce the chance of transmitting the virus.


The CDC estimates that half of people with chronic HBV are unaware of their infection. The only way to find out if you have a hepatitis B infection is to get an HBV test. All it takes is a simple blood test. Hepatitis B testing is a covered preventive service under many health plans.

Being aware of your hepatitis B status is important because treatments are available that reduce the chance of developing liver disease and liver cancer. If you are diagnosed with HBV, you can also protect your family members by getting them vaccinated.

The following populations are at increased risk of becoming infected with HBV and are recommended to be tested:

  • Infants born to HBV-infected mothers
  • Sex partners of HBV-infected persons
  • Sexually active persons who are not in a long-term, mutually monogamous relationship (e.g., >1 sex partner during the previous 6 months)
  • Men who have sex with men
  • Injection drug users
  • HIV-positive persons
  • Pregnant women
  • Incarcerated persons
  • Household contacts of persons with chronic HBV infection
  • Health care and public safety workers at risk for occupational exposure to blood or blood-contaminated body fluids
  • Hemodialysis patients
  • Residents and staff of facilities for developmentally disabled persons
  • Travelers to countries with intermediate or high prevalence of HBV infection


There are several antiviral treatments available for chronic HBV infection and everyone with chronic HBV should be linked to care, considered for treatment, and regularly checked for liver damage and liver cancer. Hepatitis B treatments reduce the amount of virus in the body and reduce the chance of developing serious liver disease and liver cancer. However, most people cannot be cured of HBV and treatment is recommended to continue for the rest of the person’s life. Research is ongoing for more effective treatments and a cure for HBV.

Take action! Three online tools help consumers understand and locate recommended hepatitis B and hepatitis C preventive and screening services.

Help Raise Awareness About Hepatitis B

Know Hepatitis B – CDC’s Hepatitis B Education Campaign for Asian Americans, Pacific Islanders, and others at risk

Learn More About Hepatitis B

Centers for Disease Control and Prevention, Division of Viral Hepatitis

National Institutes of Health

HHS Office of Women’s Health

Find additional learning opportunities for both the public and healthcare providers.

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Content created by Office of Infectious Disease and HIV/AIDS Policy (OIDP)
Content last reviewed on January 30, 2019